public class Clock {
    private homeworktow hour=new homeworktow(24);
    private homeworktow minute=new homeworktow(60);
    public void start(){
        while(true)
        {
            minute.increse();
            if(minute.getVaule()==0)
            {
                hour.increse();
            }
            System.out.printf("%02d:%02d\n",hour.getVaule(),minute.getVaule());
        }

    }
    public static void main(String[] args) {
        Clock clock=new Clock();
        clock.start();
    }
    public static class homeworktow {
        private int vaule;
        private int limit;
        public homeworktow(int limit)
        {
            this.limit=limit;
        }
        public void increse()
        {
            vaule++;
            if(vaule==limit)
            {
                vaule=0;
            }
        }
        public int getVaule()
        {
            return vaule;
        }
        //    public static void main(String[] args) {
        //        Scanner in=new Scanner(System.in);
        //        Clock.homeworktow a=new Clock.homeworktow(in.nextInt());
        //        for(;;)
        //        {
        //            a.increse();
        //            System.out.println("value="+a.getVaule());
        //        }
        //    }
    }
}
